South Sudanese refugee girl displaced by fighting, arrives at Imvepi settlement in Arua district

PAGARINYA, Uganda (Reuters) - A year ago the view from Ugandan teacher Richard Inyani's mud hut was wilderness, land untouched since the 1990s and the murderous rampages of Joseph Kony's Lord's Resistance Army.

Now it's a sprawl of tarpaulin shacks housing thousands of South Sudanese, refugees fleeing a three-year civil war that has triggered the biggest cross-border exodus in Africa since the 1994 Rwandan genocide.

And they keep coming: Last week, more than 3,000 people arrived at the border in a single morning after an alleged massacre by South Sudan government troops in Pajok, a South Sudanese town with a population of some 50,000.

Pajok is now empty, refugees say.

The influx of refugees is testing Uganda's generosity. While Inyani is happy to help fellow Africans in their hour of need - many Ugandans, including President Yoweri Museveni, were once refugees themselves - he is less enthusiastic about the sea of U.N. blue-and-white on his doorstep.

One top government official said that Uganda's system of accommodating refugees, routinely touted as one of the world's most progressive, was on the brink of "explosive" collapse.

Uganda's system allows villagers in impoverished border regions to donate land to refugees on the expectation that the foreign donor funds that support the refugees will also help the villages in the form of shared public services such as schools, roads, wells and clinics.

The problem is that aid flows are not keeping up with the scale of the exodus from South Sudan - at least 832,000 have arrived in Uganda since fighting erupted in July last year - and the system is tottering.

Inyani's village is one of those that donated hundreds of hectares of land expecting lots of investment in return.

Some of it - like the new clinic on the edge of the Pagarinya settlement - has appeared. The clinic was paid for by the United Nations refugee agency UNHCR and built by the Lutheran World Federation, a Christian charity. Two Ugandan nurses working inside said they were paid by Medical Teams International, a U.S. Christian aid group.

But the new school in Pagarinya is massively overcrowded, the new bore-holes are too far for the Ugandans to use, there are no new jobs and, with refugees having cut down most of the trees in the area for firewood and shelter, the wind is whipping across the plains, churning up dust.

Throat infections are on the rise and Inyani says the ancestral spirits are upset.

"We looked at the refugees as a positive thing because it was meant to bring development," he told Reuters, as he mixed mud cement for a relative's hut. "Instead, it's just another headache."

He is not alone in his frustration.

Last week, South Sudan's Tamazuj news agency said four South Sudanese in Bidi Bidi, a 250-sq-km (100-sq-mile) settlement housing nearly 300,000 people, the world's largest refugee camp in terms of numbers, were attacked by machete-wielding members of their Ugandan "host community".

"We have been given only one primary school and it is accommodating nearly 5,000 children. You can imagine how difficult the situation is," refugee elder Simon Lado was quoted as saying.

"The problem began when rumours circulated around that a woman refugee poisoned a child, and then the fight began. No one has died but four refugees were wounded seriously."

Bidi Bidi camp commandant Robert Baryamwesiga said he was unaware of the incident.

"BREAKING POINT"

Under a Ugandan law passed in 2006, refugees are granted freedom of movement, employment rights and access to public clinics and schools.

Each family is also given a 30m x 30m plot of land on which to build huts, and a larger 100m x 100m plot on which to grow subsistence crops, to make them self-sufficient as quickly as possible.

The system has made Uganda a frequent sanctuary for those fleeing the many conflicts that have roiled Africa's Great Lakes over the last three decades.

"It's inherent in our traditional, historical and cultural practices to support and assist a neighbour in need," Prime Minister Ruhakana Rugunda told Reuters.

But without money, the system breaks down.

The United Nations refugee agency says it has secured just 10 percent of the estimated $300 million required for the South Sudanese refugees in Uganda this year, leaving it unable to meet the basic needs of refugees or locals.

UNHCR officials said Uganda's crisis was also competing with other humanitarian disasters in Africa, most notably drought in Somalia and food shortages in northeast Nigeria stemming from Boko Haram's six-year jihadist insurgency.

"There is a continuous influx and there are no corresponding resources from the international community," said the top Ugandan government official.

"If we don't get the support, I think the situation will reach explosive levels."

"THE LAND IS OURS"

Kampala is in talks with the World Bank for a $50 million 5-year loan to help refugee-hosting communities, the official said. In the meantime, it has begun to curb its generosity.

Dozens of refugees interviewed by Reuters said they or friends had missed out recently on the standard monthly food ration of 12 kg of maize and 4 kg of beans.

Furthermore, none of the refugees interviewed by Reuters, including some who had been in Uganda since 2014, said they had received more than the standard 30m x 30m housing plot.

"It's getting tougher," said Mark Manyuon, a 26-year-old South Sudanese who has been in Uganda for nearly three years. "You have to decide to eat just once a day."

Without access to fertile land for cultivation - the soil in Pagarinya is stony and poor - they will remain reliant on handouts coordinated by the U.N.'s World Food Programme.

Ugandan officials acknowledge shortcomings but said farmland would be allocated once the immediate crisis had been dealt with.

"In an emergency, you're just thinking about saving lives. The rest can come later," said Godfrey Byaruhanga, commandant of the Palorinya camp 40 km (25 miles) away that houses 148,000 South Sudanese, more than the Ugandan population of the district in which it sits.

But with South Sudan's civil war producing weekly reports of ethnic atrocities, there is little chance of the 'emergency' ending any time soon.

Overall, the fighting has uprooted more than 3 million South Sudanese, and by July 5.5 million - nearly half the population - are unlikely to have a reliable food supply, according to the United Nations.

Some will inevitably end up in Inyani's back yard.

"We don't want money. We just want small things: boreholes, schools, roads, development," Inyani said. "We have the power to stop this. This is our land. One time, we will act. We will stop UNHCR. The land is ours."